1. Field of the Invention
The present invention relates to a phosphor suitable for a phosphor layer of a plasma display panel.
2. Description of Related Art
A plasma display panel (hereinafter abbreviated as PDP) comprises two sheets of glass substrates having provided thereon electrodes, and a number of minute discharge spaces (hereinafter referred to as a cell) formed by partition walls provided between the substrates. On side surfaces of the partition walls surrounding each cell and the bottom surface of each cell, phosphor layers each emitting red (R), green (G) and blue (B) light are provided, and a discharge gas mainly composed of Xe, Ne, etc. is enclosed within the cell. When a voltage is applied between the electrodes for selective discharge, ultraviolet rays are generated and the phosphor is excited to emit light, whereby desired information can be displayed.
In general, a phosphor layer is formed using (Y, Gd)BO3:Eu (red), Zn2SiO4:Mn (green), BaMgAl10O17 :Eu (blue), etc. (see, e.g., Japanese Patent Application Publication-Tokukai-2002-226853 and Japanese Patent Application Publication-Tokuhyou-2001-513828) The phosphor layer is formed by coating a phosphor paste containing a phosphor within the partition walls of a panel using, for example, an ink jet nozzle, drying the coated phosphor paste and then calcining the dried phosphor paste (see, e.g., Japanese Patent Application Publication-Tokukai-2002-50288). With a recent tendency toward miniaturization of a discharge cell and complexity of a shape in the discharge cell, the coating of the phosphor paste using such an ink jet printing has been employed as an extremely effective method.
However, an ink jet nozzle used at the coating of phosphors has a nozzle size of from 50 μm to 100 μm and therefore, there is a problem that unless phosphors having an extremely small particle size and a uniform particle shape are used, clogging of the nozzle is easily caused. Further, there is a possibility that deterioration in luminance performance, and rapid deterioration in heat treatment resistance in a baking step after the coating of phosphor pastes, or in ultraviolet ray resistance at the discharge are caused if phosphor particles are only made fine.